Maybe I'm slow on the upkeep when it comes to cool science toys, but have you heard of magnetic putty?
What is this stuff? It looks as though it plopped out of a UFO and is slowly plotting to take over the human race. It bounces, it stretches, it does not work as a climbing rope.
I guess you can even charge the putty and it will become it's own magnet. All these extra putty functions come with a price tag. A little over 3 ounces of the stuff will run you roughly $15. Much more than the dollar putty I used to use on the funny section in the Sunday newspaper.